[PATCH 6.4 646/800] pwm: imx-tpm: force real_period to be zero in suspend

Greg Kroah-Hartman
2023-07-16T20:23:05Z

From: Fancy Fang <chen.fang@nxp.com>

[ Upstream commit 661dfb7f46298e53f6c3deaa772fa527aae86193 ]

During suspend, all the tpm registers will lose values.
So the 'real_period' value of struct 'imx_tpm_pwm_chip'
should be forced to be zero to force the period update
code can be executed after system resume back.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pwm/pwm-imx-tpm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 5e2b452ee5f2e..98ab65c896850 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -397,6 +397,13 @@ static int __maybe_unused pwm_imx_tpm_suspend(struct device *dev)
if (tpm->enable_count > 0)
return -EBUSY;

+ /*
+ * Force 'real_period' to be zero to force period update code
+ * can be executed after system resume back, since suspend causes
+ * the period related registers to become their reset values.
+ */
+ tpm->real_period = 0;
+
clk_disable_unprepare(tpm->clk);

return 0;
--
2.39.2